Chapter 15: The Chromosomal Basis of Inheritance (1)

Mendel's "factors" are __, which are located along chromosomes.

Using improved techniques of microscopy, cytologists worked out the process of ___ in 1877 and __ in the 1890s.
--> __ and __ converged when biologists began to see parallels between the behavior of __ and the behavior of Mendel's proposed ___ during sexual life cycles:
-----------__ and __ are both present in pairs in __ cells; __ separate and __ segregate during the process of meiosis; and __ restores the paired conditions for both chromosomes and genes.

Around 1902, Walter S. Sutton, Theodor Boveri, and others independently noted these parallels, and the ___ began to take form.

What is the chromosome theory of inheritance?

Behavior of __ during meiosis can account for the segregation of the __ at each genetic __ to different __.

The behavior of _ can account for the independent assortment of the __for two or more genes located on different chromosomes.

Thomas Hunt Morgan, for his experiment, used a __.
-- Why?

True or False: Morgan got no results for two years, but was rewarded with the discovery of a single male fly with white eyes instead of the usual red.
True False

The phenotype for a character most commonly observed in natural populations, such as red eyes in Drosophila, is called a __.

Traits that are alternatives to the wild type, like white eyes of Drosophila, are called __ because they are due to alleles assumed to have originated as changes, or mutations in the wild type allele.

Morgan invented notation for symbolizing alleles in fruit flies:
- For a given character in flies, the gene takes its symbol from the first __ discovered.
---- The allele for white eyes is symbolized by __, and the wild type trait is __, for red eyes.

What were Morgan's results when he mated his white-eyed male fly with a red-eyed female?

The correlation between the trait of white eye color and the male sex of the afffected F2 flies suggested to Morgan that the gene iinvolved in his white-eyed mutant was located exclusively on the __, with no corresponding allele present on the __.

Fly results:
- For a mlae, a single copy of the __ would confer white eyes; since a male has only one __ chromosome, there can be no __ present to offset the __ allele.
- On the other hand, a female could have white eyes only if both her __ chromosomes carried the recessive __. THis was impossible for the F2 females because the F1 fathers had red eyes.
- His findings of the correlation between a particular trait and an individual's sex provided support for the __: namely, that a specific gene is carried on a specific chromosome.
- In addition, his work indicated that genes located on a __ chromosome exhibit unique inheritance patterns.